Labdoor analyzed 66 best-selling multivitamin supplements in the United States, measuring levels of key vitamins (A, B3, B6, C, D, and folic acid), minerals (calcium, iron, magnesium, manganese, phosphorus, potassium, sodium, and zinc), fatty acids (total omega-3, EPA, and DHA), and heavy metals (arsenic, lead, cadmium, bismuth, antimony, and silver).
The products tested missed their vitamin label claims by an average of 21.6% and missed their mineral label claims by an average of 41.3%. Supplement labels most commonly overstated their claims for vitamins A and C, with 12 multivitamins containing at least 30% less vitamin A vs. their label claims and 16 multivitamins containing at least 10% less vitamin C vs. their label claims.
Samples of every multivitamin passed all six heavy metals assays. Five products contained at least one artificial color (Blue 1, Blue 2, Red 40, Yellow 5, or Yellow 6). Three products recorded benzoic acid and/or caramel color.
12 multivitamins (16%) contained at least 30% less vitamin A vs. their label claims.
Average absolute variance ranged from 17.1% (vitamin C) to 29.4% (vitamin B-6) in vitamin content and from 10.9% (Zinc) to 113.8% (Phosphorus) in mineral content. Both products with claimed omega-3 content met or exceeded their label claims.
Supplement labels most commonly overstated their claims for vitamins A and C, with 12 multivitamins containing at least 30% less vitamin A vs. their label claims and 16 multivitamins containing at least 10% less vitamin C vs. their label claims. Additionally, 17 products contained at least 10% less zinc vs. their label claims.
All 66 multivitamins passed heavy metal screenings for arsenic, cadmium, and lead (<1 PPM).
All 66 multivitamins were screened by Inductively Coupled Plasma (ICP)-based techniques for the presence of heavy metals. Samples of every multivitamin passed all six heavy metals assays, indicating that samples contained under 1 PPM (part per million) each of arsenic, lead, cadmium.
Gummy vitamins represented three of the bottom five products for Nutrition Value in this category.
Multivitamins averaged a 7.4/10 rating for Nutritional Value.
11 of the 66 multivitamins listed values higher than 10 calories per serving, and only 1 product exceeded 4g of sugar.
7 products utilized coloring agents that have been linked to adverse health effects, including hypersensitivity and cancer.
One focus of our Ingredient Safety analysis was on products that exceeded the tolerable upper limit (TUL) of fat-soluble vitamins. Six products exceeded the TUL for vitamin A (10,000 IU) in a single serving. One product, Myogenix MyoVite, was measured at 5,500 IU of vitamin D-3 per serving, exceeding the TUL of vitamin D-3 (4,000 IU).
23 multivitamins recorded vitamin B3 levels above 35mg, the recommended upper intake level published by the Institute of Medicine (IOM). Acute vitamin B-3 toxicity may cause flushing of the skin, increased heart rate, and nausea; chronic toxicity may lead to liver damage and ulceration of the stomach.
Mineral content was well below published TULs in most multivitamins. Bodybuilding.com Foundation Series Multivitamin was one notable exception, exceeding the TUL of zinc in one serving. Acute zinc toxicity may cause gastrointestinal distress; chronic toxicity is associated with immune dysfunction and impaired cholesterol regulation.
42 of the 66 multivitamins tested were found to contain at least 50% of the recommended daily value for six key vitamins (vitamins A, B3, B6, B9, C, and D).
Vitamin and mineral supplementation is expected to be most effective when nutrient deficiencies are present. In developed countries, the majority of adults consume adequate quantities of these nutrients in their everyday diets.
Multivitamins are frequently recommended to specific populations, such as women who may be nursing or pregnant (due to the increased need for vitamins and minerals), people with restrictive diets (who may have gaps in their nutrient consumption), and the elderly (who tend to be at higher risk for nutrient deficiencies).